1. Field of the Invention
The present invention relates to a transfer method suitably applicable to a system including a device that performs input or output in accordance with a digital video/sound input/output interface standard called a “High-Definition Multimedia Interface (HDMI) standard”, a transfer device applicable to the transfer method, and a program implemented in the transfer device.
2. Description of the Related Art
An “HDMI standard” has been proposed as an interface standard for a network allowing transfer of uncompressed digital video data, for example, between a plurality of video devices. In accordance with the HDMI standard, video data is transferred individually pixel by pixel as primary color data. Sound data (audio data) is transferred using a transfer line for video data during a blanking period of the video data. The primary color data to be transferred includes primary color data for red, green, and blue (R data, G data, and B data). Luminance and color-difference signals such as Y, Cb, and Cr may be transferred instead of the primary color data.
A network formed by connection through a transfer line according to the HDMI standard may include, for example, devices mainly for transmitting or receiving video or sound such as a television receiver, a video recording/playback device, a video playback device, and a computer device. The connection through a transfer line according to the HDMI standard enables transfer of video contents and sound contents. Besides the line and period for transferring video content data and sound content data, a line and period for transferring control data for controlling a recipient device may also be provided. In the description below, a network formed by connection through a transfer line according to the HDMI standard is referred to as an “HDMI network”.
Meanwhile, a network called a “Local Area Network (LAN)” is widely used as a wired or wireless network. In case the of a wired LAN, for example, devices are connected using a LAN cable such as a twisted pair cable, and a router provided on the network assigns an IP address to respective devices in the network to allow communication. In case the of a wireless LAN, communication between the devices and the router is performed wirelessly. In the description below, a network in which transfer is performed using an IP address is referred to as an “IP network”.
In the case where a device connected to a LAN (an IP network) is also connected to the Internet as an external network, a router having a relay function (routing function) assigns an IP address according to rules of the Internet (such as a global IP address) to the device so that the device may communicate with various servers on the Internet. In the case where a device connected to a LAN is not connected to the Internet, on the other hand, the router assigns an IP address, which is private to the LAN, (such as a private IP address) to the device.
In recent years, various video devices connectable to a LAN such as television receivers have been commercialized along with the widespread proliferation of Internet connection through fiber optics. The connectability to the Internet by way of a LAN makes it possible to acquire via the Internet, display, and accumulate video contents and sound contents accumulated in an external server. Besides acquiring contents such as video contents, the connectability to the Internet also makes it possible to acquire data on a program table, update software for a device connected to the network, and so forth. The connectability to the Internet further makes it possible to make a reservation to record a program on a device having a recording/playback function from an external device connected to the Internet.
In case the of a video device connectable to a LAN, the video device itself may include a built-in router (routing function section) for assigning an IP address.
Japanese Unexamined Patent Application Publication No. 2002-232377 discloses the details of data transfer according to the HDMI standard.
Japanese Unexamined Patent Application Publication No. 2007-143059 discloses transmission and reception of video using an IP address.